珠海电厂精处理系统再生废水综合利用改造方案

Comprehensive Utilization of Resin Regenerating Wastewater in Zhuhai Power Plant

针对珠海电厂凝结水精处理系统再生废水氨氮含量严重超标问题,在摸清水量、水质特点和分析全厂废水氨氮排放状况的基础上,提出了脱气膜氨氮去除、反渗透浓缩-电解制氯和氨氮吹脱-磷酸吸收-回用渣水系统3种废水综合利用工艺方案,并进行了深入的对比研究。结果表明:利用吹脱吸收工艺对凝结水精处理系统再生废水中大部分氨氮予以去除后,将其补入渣水系统的综合利用方案最具可行性,投资和运行费用均比较低,工艺成熟可靠;同时采用磷酸溶液吸收含氨尾气,生成有用的肥料,无二次污染。珠海电厂采用该方案并于2018年实施,投运近半年来,精处理再生废水氨氮平均质量浓度由原来的280～420mg/L降至30～60 mg/L,去除效率稳定在85%以上,优于设计指标。

Regarding the problem of excessive ammonia nitrogen content in reclaimed wastewater of condensate treatment system in Zhuhai power plant, three kinds of comprehensive utilization programs, i.e., membrane absorption, reverse osmosis concentrationelectrolysis and ammonia stripping-phosphoric acid absorption-reuse to slag water system, were put forward and a thorough comparative study was carried out on the basis of the investigation of water quantity and water quality characteristics and the analysis of ammonia nitrogen discharge of the whole plant wastewater. The results show that after the removal of most ammonia nitrogen in the regenerated wastewater through the process of blowing and absorption, the comprehensive utilization scheme that reuse this part of the wastewater to the slag water system is the most feasible solution with low investment and operating costs while the application techniques are mature and reliable. Meanwhile, phosphoric acid solution is used to absorb ammonia tail gas to produce useful fertilizers without secondary pollution. The scheme was adopted by Zhuhai power plant and implemented in 2018. The actual operation effect is satisfactory. After the operation into service for nearly half a year, the average concentration of ammonia nitrogen from recycled wastewater was reduced from 280~420 mg/L to 30~60 mg/L, and the removal efficiency was over 85%, which exceed the requirements of design specifications.